When you replace an image with a new upload it can take 24 to 48 hours for the new image to show.
It may take longer for some areas to convert to the new image.
If your patience is wearing thin after 48 hours you can try to Clear Your Cache / History from your browser.
If you don’t mind losing your analytics and breaking any links you posted to social media you can delete the old upload completely and start over – giving the new unloaded image a new title, change the filename and upload with only one browser tab open to FAA/Pixels. - This will post your new image immediately and prevent any future problems with identical titles on the site.